"TMSU is a tool for tagging your files. It provides a simple command-line utility for applying tags and a virtual filesystem to give you a tag-based view of your files from any other program.

TMSU does not alter your files in any way: they remain unchanged on disk, or on the network, wherever your put them. TMSU maintains its own database and you simply gain an additional view, which you can mount where you like, based upon the tags you set up."

Interesting application of file tagging with a sqlite db in the background. Can be used to view your files in a virtual fs as tagged and so on. On the other hand, the vfs makes use of soft links and not hard links like I would have presumed.